Process and device for treating a biomass mixed with water in order to produce drinking water, biogas and combustible solids

Abstract

The present invention relates to a process for treating a biomass ( 1 ) mixed with water in order to produce, independently, combustible solids ( 14 ) and drinking water ( 12 ) and biogas ( 13 A, 13 B), and also to a device for treating a biomass ( 1 ) mixed with water in order to produce, independently, combustible solids ( 14 ), drinking water ( 12 ) and biogas ( 13 A, 13 B).

The invention claimed is: 
     
       1. A method for treating a biomass ( 1 ) mixed with water for producing in a decoupled way combustible dry materials ( 14 ), drinkable water ( 12 ) and a biogas including a first fraction of biogas ( 13 A),
 the drinkable water ( 12 ) not containing any suspended material and having a dry material content strictly less than 1%, 
 said method successively comprising the following steps: 
 (a) subjecting the biomass ( 1 ) mixed with water to anaerobic fermentation in an anaerobic fermenter ( 2 ) to produce a concentrated liquid digestate ( 17 ) and the first fraction biogas ( 13 A), wherein the anaerobic fermenter comprises at least two output conduits ( 3 A,  3 B); 
 (b) pumping and milling a portion of the concentrated liquid digestate ( 17 ) by a pump/milling machine ( 4 ) to produce a milled concentrated liquid digestate ( 27 ) containing fibers and particles; 
 (c) separating, using a separator ( 5 ), the fibers and the particles in said milled concentrated liquid digestate ( 27 ) to produce a clarified water ( 24 ) and a milled concentrated humid digestate ( 25 B); 
 (d) feeding the clarified water ( 24 ) into a water extractor ( 6 ) to produce drinkable water ( 12 ) and a remnant of a milled liquid digestate ( 25 A), wherein a first portion of the remnant of a milled liquid digestate ( 25 A) is mixed with the clarified water ( 24 ) before the water extractor ( 6 ); 
 (e) passing a second portion of the remnant of the milled liquid digestate ( 25 A) through a first lysis device ( 18 A) and subsequently adding the resulting stream with the milled concentrated humid digestate ( 25 B) to obtain a milled and lyzed concentrated humid digestate ( 37 ); 
 (f) returning the milled and lyzed concentrated humid digestate ( 37 ), without any loss thereof, to the anaerobic fermenter ( 2 ); 
 (g) passing a portion of the concentrated liquid digestate ( 17 ) through the output conduit ( 3 B) of the anaerobic fermenter ( 2 ) to a dehydration device ( 16 ) to produce the combustible dry materials ( 14 ) and dehydration water ( 15 ), returning the dehydration water ( 15 ) directly to the anaerobic fermenter ( 2 ), wherein the concentrated liquid digestate ( 17 ) is mixed in the anaerobic fermenter ( 2 ) with the milled and lyzed concentrated humid digestate ( 37 ) after totally re-injecting the milled and lyzed concentrated humid digestate ( 37 ) into the anaerobic fermenter ( 2 ). 
 
     
     
       2. The method according to  claim 1 , wherein,
 in step (a), the concentrated liquid digestate ( 17 ) lies at a bottom portion of anaerobic fermenter ( 2 ), and 
 in step (b) pumping of the portion of the concentrated liquid digestate ( 17 ) is carried out from the bottom portion of the anaerobic fermenter ( 2 ). 
 
     
     
       3. The method according to  claim 1 , further comprising least one additional step applied at a conduit ( 42 ) connected to the water extractor ( 6 ), wherein the additional step controls the quality of the drinkable water ( 12 ) by means of turbidity and conductivity. 
     
     
       4. The method according to  claim 1 , further comprising at least one additional step applied at the conduit ( 3 A), wherein the additional step controls the quality of the biomass ( 1 ) by means of viscosity and by a measurement of biodegradability. 
     
     
       5. A device for treating a biomass ( 1 ) mixed with water in order to produce in a decoupled way combustible dry materials ( 14 ), drinkable water ( 12 ), a first fraction of biogas ( 13 A), and optionally a second fraction of biogas ( 13 B), said device comprising:
 (i) an anaerobic fermenter ( 2 ) comprising at least two output conduits ( 3 A;  3 B), wherein the anaerobic fermenter ( 2 ) is configured to perform anaerobic fermentation of the biomass ( 1 ) to produce a concentrated liquid digestate ( 17 ) and the first fraction of biogas ( 13 A); 
 (ii) a pump/milling machine ( 4 ) for pumping and milling a portion of the concentrated liquid digestate ( 17 ) to produce a milled liquid digestate ( 27 ) comprising fibers and particles, wherein the pump/milling machine ( 4 ) is connected to the anaerobic fermenter ( 2 ) by the output conduit ( 3 A); 
 (iii) a separator ( 5 ) for separating fibers and particles from the milled liquid digestate ( 27 ) to produce clarified water ( 24 ) and a milled concentrated humid digestate ( 25 B), wherein the separator ( 5 ) is connected to the pump/milling machine ( 4 ); 
 (iv) a water extractor ( 6 ) for treating the clarified water ( 24 ) to produce drinkable water ( 12 ) and a remnant of a milled liquid digestate ( 25 A), wherein the water extractor ( 6 ) is connected to the separator ( 5 ); 
 (v) a first lysis device ( 18 A), adapted for lyzing a portion of the remnant of the milled liquid digestate ( 25 A), a second lysis device ( 18 B), adapted for lyzing a mixture of the milled concentrated humid digestate ( 25 B) and a milled and lyzed concentrated humid digestate ( 37 ) obtained after the first lysis device ( 18 A), wherein the first lysis device ( 18 A) is connected to the water extractor ( 6 ) and the second lysis device ( 18 B) is downstream from the first lysis device ( 18 A); 
 (vi) a conduit ( 40 B), which allows the milled and lyzed concentrated humid digestate ( 37 B) to flow out of the second lysis device ( 18 B) without any loss thereof and to be returned to the anaerobic fermenter ( 2 ); 
 (vii) at least one dehydration device ( 16 ) for receiving at least a portion of the concentrated liquid digestate ( 17 ) to produce the combustible dry materials ( 14 ) and a dehydration water ( 15 ), wherein the at least one dehydration device ( 16 ) is connected through the outlet conduit ( 3 B) to the anaerobic fermenter ( 2 ). 
 
     
     
       6. The device according to  claim 5 , wherein the output conduit ( 3 A) allows a portion of the concentrated liquid digestate ( 17 ) to flow out of the bottom of the anaerobic fermenter ( 2 ) and to enter the pump/milling machine ( 4 ). 
     
     
       7. The device according to  claim 5 , wherein the separator ( 5 ) receives a portion of the milled liquid digestate ( 27 ) and discharges a milled concentrated humid digestate ( 25 B) and clarified water ( 24 ), and wherein the separator ( 5 ) is connected to the pump/milling machine ( 4 ) through at least one conduit ( 38 ) and connected to the water extractor ( 6 ) through at least one conduit ( 41 ). 
     
     
       8. The device according to  claim 5 , further comprising
 a second anaerobic fermenter ( 10 ), wherein the second anaerobic fermenter ( 10 ) produces the second fraction of biogas ( 13 B), wherein the second anaerobic fermenter ( 10 ) is connected to the second lysis device ( 18 B) through at least one conduit ( 40 A). 
 
     
     
       9. The device according to  claim 8 , wherein a third lysis device ( 18 C) is connected to the separator ( 5 ) through at least one conduit ( 8 ), the first lysis device ( 18 A) is connected to the water extractor ( 6 ) through at least one conduit ( 39 ) and the second lysis device ( 18 B) is directly connected to the first lysis device ( 18 A) through a conduit ( 9 A). 
     
     
       10. The device according to  claim 8 , wherein the bottom of the first anaerobic fermenter ( 2 ) is connected to the second anaerobic fermenter ( 10 ) through at least one conduit ( 3 C) leading a portion of the liquid digestate ( 17 ) to the second anaerobic fermenter ( 10 ). 
     
     
       11. The device according to  claim 8 , wherein the separator ( 5 ) is connected to:
 at least one conduit ( 41 ) to allow the clarified water ( 24 ) to flow from the separator ( 5 ) to the water extractor ( 6 ), 
 at least one conduit ( 8 ) to allow the milled concentrated humid digestate ( 25 B) to flow from the separator ( 5 ) to the third lysis device ( 18 C) and, 
 optionally, a conduit ( 11 ) for recycling a portion of the milled concentrated digestate ( 25 B) to the pump/milling machine ( 4 ). 
 
     
     
       12. The device according to  claim 5 , wherein the pump/milling machine ( 4 ) is immersed inside the anaerobic fermenter ( 2 ). 
     
     
       13. The device according to  claim 8 , wherein
 the at least one dehydration device ( 16 ) is optionally connected to the second anaerobic fermenter ( 10 ) by a conduit ( 3 E). 
 
     
     
       14. The device according to  claim 8 , wherein the dehydration water ( 15 ) from the at least one dehydration device ( 16 ) is recycled to at least one anaerobic fermenter ( 2 ,  10 ) through at least one conduit ( 15 A). 
     
     
       15. A method for treating a biomass ( 1 ) mixed with water for producing in a decoupled way combustible dry materials ( 14 ), drinkable water ( 12 ) and a first fraction of biogas ( 13 A), and a second fraction of biogas ( 13 B), the drinkable water ( 12 ) not containing any suspended material and having a dry material content strictly less than 1%,
 said method successively comprising the following steps: 
 (a) subjecting the biomass ( 1 ) mixed with water to anaerobic fermentation in a first anaerobic fermenter ( 2 ) to produce a concentrated liquid digestate ( 17 ) and the first fraction of biogas ( 13 A), wherein the first anaerobic fermenter comprises at least two output conduits ( 3 A;  3 B), which are connected to the first anaerobic fermenter ( 2 ); 
 (b) pumping and milling a portion of the concentrated liquid digestate ( 17 ) by a pump/milling machine ( 4 ) to produce a milled concentrated liquid digestate ( 27 ) containing fibers and particles, 
 (c) feeding a portion of the concentrated liquid digestate ( 17 ) to a second anaerobic fermenter ( 10 ); 
 (d) separating, using a separator ( 5 ), the fibers and the particles in the milled concentrated liquid digestate ( 27 ) to produce clarified water ( 24 ) and a milled concentrated humid digestate ( 25 B); 
 (e) feeding said clarified water ( 24 ) into at least one water extractor ( 6 ) to produce the drinkable water ( 12 ) and a remnant of a milled liquid digestate ( 25 A), wherein a first portion of the remnant of milled liquid digestate ( 25 A) is mixed with the clarified water ( 24 ) before the water extractor ( 6 ); 
 (f) passing a second portion of the remnant of milled liquid digestate ( 25 A) through at least one lysis device ( 18 A) and subsequently adding the resulting stream with the milled concentrated humid digestate ( 25 B), which is optionally passed through at least one lysis device ( 18 C), to obtain a milled and lyzed concentrated humid digestate ( 37 ); 
 (g) returning the milled and lyzed concentrated humid digestate ( 37 ), without any loss thereof, 
 to the second anaerobic fermenter ( 10 ), and optionally to the first anaerobic fermenter ( 2 ), for producing the second fraction of biogas ( 13 B), 
 wherein the second anaerobic fermenter ( 10 ) comprises at least two output conduits ( 3 E,  3 F) connected to the second anaerobic fermenter ( 10 ); 
 (h) passing a portion of the concentrated liquid digestate ( 17 ) through the output conduit ( 3 B) of the first anaerobic fermenter ( 2 ), and optionally through the output conduit ( 3 E) of the second anaerobic fermenter ( 10 ), to a dehydration device ( 16 ), wherein the dehydration device ( 16 ) produces the combustible dry materials ( 14 ) and dehydration water ( 15 ), and the dehydration water ( 15 ) is returned directly to the first anaerobic fermenter, ( 2 ) and optionally to the second anaerobic fermenter ( 10 ), wherein the concentrated liquid digestate ( 17 ) is mixed, in the first and second anaerobic fermenters ( 2 , 10 ), with the milled and lyzed concentrated humid digestate after totally re-injecting the milled and lyzed concentrated humid digestate into the first and second anaerobic fermenters ( 2 ,  10 ).